South Korea's terms of trade worsened last year as export prices fell at a faster pace than import prices on weak global demand, central bank data showed Monday.

Net terms-of-trade index for goods declined 2.4 percent in 2012 from a year earlier, according to the Bank of Korea (BOK). The index is calculated by dividing export prices by import prices, reflecting the amount of goods that the country can import with a unit of export.

The decline came as weak global demand arising from the eurozone fiscal crisis and the global economic slump dragged down the country's export prices at a faster pace than import prices.

Income terms-of-trade index, which reflects export volume in trade terms, increased 3.1 percent in 2012 from a year before as the export amount grew amid the price competitiveness stemming from lower prices. The index is calculated by multiplying the terms-of-trade index by the export volume.

South Korea's trade surplus fell to 28.6 billion U.S. dollars in 2012 from 30.8 billion dollars in the prior year, but the trade volume topped 1 trillion dollars for two straight years. The export-driven economy beat Italy to become the world's eighth- largest trading partner last year.